1. Field of the Invention
This invention relates generally to the design of electro-optic imaging systems, and more particularly, to the “end-to-end” design of these systems using nonequidistant discrete Fourier transforms, including for example the nonequidistant fast Fourier transform.
2. Description of the Related Art
Electro-optic imaging systems typically include an optical subsystem (e.g., a lens assembly), an electronic detector subsystem (e.g., CCD detector array) and a digital image processing subsystem (e.g., typically implemented in dedicated chips or software). Traditional methods for designing these systems generally involve two discrete stages. First, the optical subsystem is designed with the goal of forming a high quality intermediate optical image of the source (subject to cost, physical and other non-imaging constraints). Next, after the optical subsystem has been designed, the digital image processing subsystem is designed to compensate for remaining defects in the sampled intermediate optical image.
The two design stages typically occur with very little coordination between the optical designer and the image processing designer. One drawback to the traditional design approach is that synergies between the optical subsystem and the digital image processing subsystem may be overlooked. There may be unwanted interactions between the two independently designed subsystems and potential synergies between the two subsystems may go unrealized.
Recently, more holistic design approaches have been proposed. For example, see U.S. patent application Ser. No. 11/155,870, “End-to-End Design of Electro-Optic Imaging Systems,” which is incorporated by reference herein. These design processes combine traditional optical design with digital imaging processing, including characteristics of the imaging sensor. This provides a framework for the end-to-end design of a complete electro-optic imaging system.
The design process typically includes an optimization step that jointly optimizes parameters for the optical subsystem, the detector subsystem and/or the digital image processing subsystem. At each iteration of the optimization, the overall performance of the electro-optic imaging system is modeled, including propagation through each of the subsystems. This modeling is used to calculate a performance metric. The performance metric is optimized with respect to the design parameters. However, modeling propagation through each of the subsystems can be computationally time-consuming, which in turn results in a slow optimization and long design cycle.
Thus, there is a need for faster design techniques based on an end-to-end design of the electro-optic imaging system.